Method and system for dynamic power allocation in a transport refrigeration system

ABSTRACT

A method and system for dynamic power allocation in a transport refrigeration system (TRS) is provided. The method includes a TRS power source operating in an operational state. The method also includes monitoring an amount of current being drawn from one or more generator powered components of the TRS. Also, the method includes calculating, via a TRS controller of the TRS, a maximum available horsepower amount based on the amount of current being drawn from the one or more generator powered components. Further, the method includes controlling, via the TRS controller, an amount of horsepower directed to a compressor of the TRS based on the maximum available horsepower amount.

FIELD

Embodiments of this disclosure relate generally to a transportrefrigeration system (TRS). More specifically, the embodiments relate toa method and system for dynamic power allocation in a TRS.

BACKGROUND

A transport refrigeration system (TRS) is generally used to control anenvironmental condition (e.g., temperature, humidity, air quality, andthe like) within a refrigerated transport unit (e.g., a container on aflat car, an intermodal container, etc.), a truck, a box car, or othersimilar transport unit (generally referred to as a “refrigeratedtransport unit”). Refrigerated transport units are commonly used totransport perishable items such as produce, frozen foods, and meatproducts. Typically, a transport refrigeration unit (TRU) is attached tothe refrigerated transport unit to control the environmental conditionof the cargo space. The TRU can include, without limitation, acompressor, a condenser, an expansion valve, an evaporator, and fans orblowers to control the heat exchange between the air inside the cargospace and the ambient air outside of the refrigerated transport unit.

SUMMARY

Embodiments of this disclosure relate generally to a transportrefrigeration system (TRS). More specifically, the embodiments relate toa method and system for dynamic power allocation in a TRS.

In some embodiments, a TRS includes a dynamic power allocation system.The dynamic power allocation system can be configured to monitor acurrent draw from various generator powered components of the TRSreceiving current from a generator (e.g., an alternator and/or a TRUbattery charger) and dynamically allocate a maximum allowable power tothe compressor based on the monitored current draw.

When an electric drive motor is used, the dynamic power allocationsystem allows a power efficiency of the electric drive motor to bemaximized. Accordingly, a maximum allowable horsepower can bedynamically allocated to the compressor thereby utilizing a truepotential of the electric drive motor as opposed to, for example,setting a predefined limit as to the amount of power that can beallocated to the compressor. Thus, the embodiments described herein canprevent the electric drive motor from overloading which can reduce theoverall life expectancy of the electric drive motor and can preventdamage to portions of the electric drive motor (e.g., a motor windinginsulation of the electric drive motor).

When an engine is used, the dynamic power allocation system can preventoverloading of the engine. By preventing overloading of the engine, thedynamic power allocation system can thereby prevent the TRS fromexceeding, for example, emissions limits.

In one embodiment, a method for dynamic power allocation in a TRS isprovided. The method includes a TRS power source operating in anoperational state. The method also includes monitoring an amount ofcurrent being drawn from one or more generator powered components of theTRS. Also, the method includes calculating, via a TRS controller of theTRS, a maximum available horsepower amount based on the amount ofcurrent being drawn from the one or more generator powered components.Further, the method includes controlling, via the TRS controller, anamount of horsepower directed to a compressor of the TRS based on themaximum available horsepower amount.

In another embodiment, a TRS is provided that includes a refrigerationcircuit, a TRS power source, one or more generator powered components, acurrent source and a TRS controller. The refrigeration circuit includesa compressor. The TRS power source is configured to drive thecompressor. The current source is configured to provide current to theone or more generator powered components. The TRS controller isprogrammed to monitor an amount of current being drawn from the one ormore generator powered components, calculate a maximum availablehorsepower amount based on the amount of current being drawn from theone or more generator powered components, and control an amount ofhorsepower allocated to the compressor based on the maximum availablehorsepower amount.

BRIEF DESCRIPTION OF THE DRAWINGS

References are made to the accompanying drawings that form a part ofthis disclosure, and which illustrate the embodiments in which thesystems and methods described in this Specification can be practiced.

FIG. 1 illustrates a schematic cross sectional side view of a TRS,according to one embodiment.

FIG. 2A illustrates a block diagram of a dynamic power allocation systemfor a TRS, according to one embodiment.

FIG. 2B illustrates a block diagram of a dynamic power allocation systemfor a TRS, according to another embodiment.

FIG. 3 illustrates a flowchart of a method of dynamic power allocationfor a TRS, according to one embodiment.

Like reference numbers represent like parts throughout.

DETAILED DESCRIPTION

Embodiments of this disclosure relate generally to a TRS. Morespecifically, the embodiments relate to a method and system of dynamicpower allocation for a TRS.

A TRS can include an electric drive motor configured to drive acompressor in a refrigeration circuit of the TRS. The electric drivemotor can be a three-phase alternating current (AC) motor. The electricdrive motor can be selected for a particular application based on one ormore characteristics, such as, but not limited to, the horsepoweroutput. The expected horsepower output and the actual horsepower outputof the electric drive motor can vary, according to some embodiments. Forexample, the actual horsepower output of the electric drive motor canvary as a result of slight variations in a manufacturing process, awearing of one or more portions of the electric drive motor over time,etc. Accordingly, the horsepower output of the electric drive motor canvary from motor to motor, and even over time within a given motor.

In some embodiments, the electric drive motor drives the compressor whenthe TRS is operating in an electric standby mode (e.g., an engine in theTRS is not running). Maximizing the use of the mechanical power can inturn provide a maximum output from the compressor, which can, in someembodiments, maximize the capacity of the TRS.

In order to maximize the use of mechanical power generated by anelectric drive motor of a TRS, embodiments described in this disclosurecan monitor a current draw from various generator powered componentsreceiving current from a generator (e.g., an alternator and/or a TRUbattery charger) and dynamically allocate a maximum allowable power tothe compressor based on the monitored current draw so as to maximize apower efficiency of the electric drive motor.

A “refrigerated transport unit” includes, for example, a refrigeratedcontainer (e.g., a container on a flat car, an intermodal container,etc.), a truck, a box car, or other similar transport unit.

A “transport refrigeration system” (TRS) includes, for example, arefrigeration system for controlling the refrigeration of an interiorspace of the refrigerated transport unit. The TRS may be avapor-compressor type refrigeration system, or any other suitablerefrigeration system that can use refrigerant, cold plate technology, orthe like.

A “TRS Controller” includes, for example, an electronic device that isconfigured to manage, command, direct, and regulate the behavior of oneor more TRS refrigeration components of a refrigeration circuit (e.g.,an evaporator, a condenser, a compressor, an expansion valve (EXV),etc.), a generator, an electronic throttling valve (ETV), etc.

Embodiments of this disclosure may be used in any suitableenvironmentally controlled transport apparatus, such as, but not limitedto, a container (e.g., a container on a flat car, an intermodalcontainer, etc.), a truck, a box car, or other similar refrigeratedtransport unit. The TRS may be a vapor-compressor type refrigerationsystem, or any other suitable refrigeration system that can userefrigerant, cold plate technology, or the like.

FIG. 1 illustrates one embodiment of a TRS 100 for a refrigeratedtransport unit 125. The TRS 100 includes a TRU 110 that controlsrefrigeration within the refrigerated transport unit 125. The TRU 110 isdisposed on a front wall 130 of the refrigerated transport unit 125. Therefrigerated transport unit can be a truck or trailer unit that can beattached to a tractor, a ship board container, an air cargo container orcabin, an over the road truck cabin, etc. The TRU 110 includes aprogrammable TRS Controller 135 that may comprise a single integratedcontrol unit 140 or that may comprise a distributed network of TRScontrol elements (not shown). The number of distributed control elementsin a given network can depend upon the particular application of theprinciples described herein.

The refrigerated transport unit 125 includes an internal space 150 thatcan be divided into a plurality of zones 152 (a front host zone 152 a, acenter remote zone 152 b, and a rear remote zone 152 c). The term “zone”means a portion of an area of the internal space 150. In some examples,each of the zones 152 can have a set point temperature that is the sameor different from one another, and may be separated by a wall 155.

As shown in FIG. 1, an evaporator portion 160 of the TRU 110 isconfigured to provide cooling and/or heating/defrosting to the fronthost zone 152 a. The center remote zone 152 b and the rear remote zone152 c each includes a remote evaporator unit 165 that is configured toprovide cooling and/or heating/defrosting to the center remote zone 152b and the rear remote zone 152 c, respectively. The remote evaporatorunits 165 are each fluidly connected to the TRU 110 and are part of arefrigeration circuit (not shown) that allows refrigerant to passthrough the evaporator portion 160 and the remote evaporator units 165.The TRU 110 and each of the remote evaporator units 165 also include azone temperature sensor 170 configured to measure temperature in therespective zone 152 in which the zone temperature sensor 170 is providedand send the measured zone temperature to the TRS Controller 135. Insome embodiments, the zone temperature sensors 170 can be separate fromthe remote evaporator units. Also, in some embodiments, the zonetemperature sensors 170 can be return air temperature sensors that areconfigured to measure a return air temperature of the evaporator units165.

While the zones 152 in FIG. 1 are divided into substantially equalareas, it is to be realized that the internal space 150 may be dividedinto any number of zones and in any configuration that is suitable forrefrigeration of the different zones.

Generally, the TRS Controller 135 is configured to control arefrigeration cycle of the TRS 100. In one example, the TRS Controller135 controls the refrigeration cycle of the TRS 100 to obtain variousoperating conditions (e.g., temperature, humidity, air quality etc.) ofthe internal space 150 as is generally understood in the art. This caninclude controlling operation of the refrigeration cycle such that eachof the zones 152 reach and maintain the desired set point temperature.The TRS Controller 135 is also configured to control a dynamic powerallocation system (see the dynamic power allocation systems 200, 255 inFIGS. 2A and 2B) of the TRS 100, as discussed in more detail below.

The TRS Controller 135 generally can include a processor (not shown), amemory (not shown), a clock (not shown) and an input/output (I/O)interface (not shown) and can be configured to receive data as inputfrom various components within the TRS 100, and send command signals asoutput to various components within the TRS 100. Operation of a TRSController, such as the TRS Controller 135, is discussed in more detailbelow.

FIGS. 2A and 2B illustrate block diagrams of a dynamic power allocationsystem 200, 255 for a TRS of a refrigerated transport unit, according totwo different embodiments. The dynamic power allocation systems 200, 255are configured to dynamically allocate maximum available power to acompressor 220 of the TRS when the TRS is connected to and powered by anelectric power source (e.g., shore power source) such as the externalpower source 295. This can occur, for example, when the refrigeratedtransport unit is operating in an electric standby mode whereby anengine 215 of the TRS is not running but the TRS still requires power toprovide refrigeration for the refrigerated transport unit. The electricstandby mode can be operated, for example, when the refrigeratedtransport unit is stored in a distribution yard or at an externalstorage location. This can also occur when the TRS does not include anengine or when the compressor 220 is not mechanically driven by, forexample, a drive system 225, but is an electrically driven compressor.

As shown in FIG. 2A, the dynamic power allocation system 200 includes anelectric drive motor 205, an alternator 210, and the engine 215. Theelectric drive motor 205 is configured to receive power from an externalpower source 295 and use the power to drive the drive system 225. Theelectric drive motor 205 can be a three phase alternating current motor,a single phase alternating current motor, or the like. Thespecifications of the electric drive motor 205 can be dependent on thedesign of the TRS and user requirements. For example, the electric drivemotor 205 can be an about 12 horsepower electric drive motor in someembodiments and an about 19 horsepower electric drive motor in otherembodiments. However, it is to be appreciated that the user can chooseany horsepower of the electric drive motor 205 based on therefrigeration capacity requirements desired.

The specifications of the electric drive motor 205 can also be dependenton the manufacturer. The electric drive motor 205 can be selected toreceive an appropriate voltage from an external power source 295. Forexample, the electric drive motor 205 can be an about 260 volt or anabout 480 volt three phase AC motor. In other embodiments, the voltagesupplied to the electric drive motor 205 may vary based on the externalpower source 295.

In some embodiments, the electric drive motor 205 can be a single speedmotor, a two-speed motor configured to operate between a low speed and ahigh speed, or a variable speed motor. When the electric drive motor 205is a variable speed motor, an adjustable speed drive (e.g., a variablespeed drive (VSD)) (not shown) can be used to control a speed and torqueof the electric drive motor 205.

As described herein, the external power source 295 refers to a powersource external to a TRS. In some embodiments, the external power source295 can be a land-based power source that provides grid power from anelectric utility company, a shore power source, etc. In otherembodiments, the external power source 295 can be a fuel cell, one ormore batteries, etc.

The engine 215 is configured to generate mechanical power for the TRS.The engine 215 can be an electrically controlled engine that iscontrolled by an electronic engine control unit (ECU) (not shown). TheECU can be configured to regulate an amount of fuel delivered to theengine 215 and can be configured to operate the engine 215 at multiplespeeds. The ECU is generally configured to allow the engine 215 to bemaintained at a chosen speed regardless of the load seen by the engine.As discussed below, the ECU can be controlled by a TRS controller 230and powered by the alternator 210. In some embodiments, the engine 215is a ˜12 horsepower (HP) engine. In other embodiments, the engine 215 isa ˜19 HP engine. As discussed herein, the engine 215 and the electricdrive motor 205 can each be referred to a TRS power source.

The drive system 225 transfers mechanical power generated by the engine215 or the electric drive motor 205 to the alternator 210 and thecompressor 220. In some embodiments, the drive system 225 can be, forexample, a belt (not shown), a chain (not shown), one or more clutches,etc. to drive the alternator 210 and the compressor 220.

The alternator 210 is configured to convert the mechanical energyderived from the drive system 225 into electrical energy that can beused to power various generator powered components in the TRS. Inparticular, the alternator 210 provides current to power various currentloads 251 including, for example, a fuel heater 238, a TRU battery 240,one or more solenoid valves 242 in a host zone (e.g., the front hostzone 152 a), one or more solenoid valves 244 in a remote zone (e.g., thecenter remote zone 152 b, the rear remote zone 152 c), the ECU 246, oneor more fans 248, one or more drain tube heaters 250, one or moreaccessory loads (e.g., lift gates, hydraulic cylinders, carbonatedbeverage pumps, etc.) (not shown). In some embodiments, the alternator210 is a direct current (DC) alternator that is configured to convertthe mechanical energy derived from the drive system 225 into DCelectrical energy that can be used to power various generator poweredcomponents in the TRS. In some embodiments, the alternator 210 is analternating current (AC) alternator that is configured to convert themechanical energy derived from the drive system 225 into AC electricalenergy that can be used to power various generator powered components inthe TRS

In some embodiments, the current to the TRU battery 240 can be a shuntcurrent of charge DC current to the TRU battery 240. Also, in someembodiments, the one or more solenoid valves 242, 244, the ECU 246, theone or more fans 248 and the one or more drain tube heaters 250 areconfigured run on DC current and to run off of a smart field-effecttransistor (FET) (not shown). The list of various current loads 251provided in FIGS. 2A-B are not limiting but can be any power accessorythat the TRS may provide power to that is not directly connected to theTRU battery 240. In some embodiments, the list of various current loads251 can include a power accessory that is powered by the smart FET. Asmart FET as discussed herein refers to a transistor that is capable ofproviding feedback (e.g., to the TRS Controller 230) indicating whetheran output (e.g., the various current loads 251) has created an opencircuit, a short circuit and a DC current amount drawn by the output.

The compressor 220 represents any type of compressor configured for usein the TRS. For example, the compressor 220 can be a digital scroll,reciprocating, screw, positive displacement, centrifugal, or othersuitable type of compressor for compressing a refrigerant in arefrigeration system. The compressor 220 receives refrigerant from anelectronic throttling valve (ETV) 235.

The ETV 235 can be configured to control a volume of refrigerantentering the compressor 225. The volume of refrigerant entering thecompressor 225 can determine a load on the compressor 220. For example,when a larger volume of refrigerant is being compressed, the load on thecompressor 220 is generally greater than when a smaller volume ofrefrigerant is being compressed. Accordingly, the ETV 230 can be used tocontrol a load on the compressor 220. In some embodiments, opening theETV 230 increases the volume of refrigerant entering the compressor 225and closing the ETV 230 decreases the volume of refrigerant entering thecompressor 225. The ETV 230 is controlled by the TRS controller 230 viaa rugged industrial communication link 252.

The rugged industrial grade communication link 252 can be, for example,a Controller Area Network (CAN) connection (e.g., a J1939 CANconnection), a RS45 connection, or any other rugged industrial gradecommunication bus that can be relied upon for stable and reliablecommunication between components in a TRS during transport.

The TRS Controller 230 is similar to the TRS Controller 135 shown inFIG. 1 and is configured to control a refrigeration cycle of the TRS andthe dynamic power allocation systems 200, 255.

FIG. 2B illustrates a block diagram of a dynamic power allocation system255 for a TRS of a refrigerated transport unit when the TRS, accordingto a second embodiment. The dynamic power allocation system 255 issimilar to the dynamic power allocation system 200 except the dynamicpower allocation system 255 includes a TRU battery charger 260 and doesnot include an alternator.

The TRU battery charger 260 is configured to directly receive power fromthe external power source 295 to charge the TRU battery 240. The TRUbattery charger 260 is also configured to provide current to power theother various current loads 251. In some embodiments, the TRU batterycharger 260 is configured to provide DC current to power the overvarious current loads 251. In some embodiments, the TRU battery charger260 is configured to provide AC current to power the over variouscurrent loads 251.

In some embodiments, the dynamic power allocation systems 200, 255 canalso be configured to dynamically allocate maximum available power to acompressor 220 of the TRS when the TRS is receiving power from theengine 215. In these embodiments, the dynamic power allocation systems200, 255 can prevent overloading of the engine 215. By preventingoverloading of the engine 215, the dynamic power allocation systems 200,255 can thereby prevent the TRS from exceeding, for example, emissionslimits.

Operation of the TRS Controller 230 with respect to the dynamic powerallocation systems 200, 255 is discussed below with respect to FIG. 3.

FIG. 3 illustrates a flowchart of a method 300 of dynamic powerallocation using one of the dynamic power allocation systems 200, 255 ofa TRS. The method 300 begins at 305, whereby a TRS power source of theTRS is in an operational state.

In some embodiments, this can include the electric drive motor 205 beingconnected to and powered by an electric power source (e.g., the externalpower source 295). Accordingly, at 305 the compressor 220 can drawmechanical energy from the drive system 225 via the electric drive motor205 and the various current loads 251 can draw current from a currentsource (e.g., the alternator 210 shown in FIG. 2A or the TRU batterycharger 260 shown in FIG. 2B). As discussed above, this can occur, forexample, when the refrigerated transport unit is operating in anelectric standby mode, when the TRS does not include an engine or whenthe compressor 220 is an electrically driven compressor.

In some embodiments, a TRS power source of the TRS being in anoperational state can include the engine 215 being in an operationalstate to generate power. Accordingly, at 305 the compressor 220 can drawmechanical energy from the drive system 225 via the engine 215 and thevarious current loads 251 can draw current from a current source (e.g.,the alternator 210 shown in FIG. 2A or the TRU battery charger 260 shownin FIG. 2B).

At 310, the dynamic power allocation system 200, 255 monitors an amountof current being drawn by the various current loads 251. In someembodiments, when the various current loads 251 are powered from a smartFET, the smart FET monitors the current being drawn by the variouscurrent loads 251 and generates current data indicating the amount ofcurrent being used by each of the various current loads 251 to be sentto the TRS Controller 230. In other embodiments, the TRS includes one ormore sensors that are configured to monitor the amount of current beingused by each of the various current loads 251. Also, in yet some otherembodiments, one or more of the various current loads 251 includes acurrent sensor that monitors the amount of current being used by therespective various current load 251.

In some embodiments, the dynamic power allocation system 200, 255 canmonitor an amount of current being drawn by the various current loads251 in real-time. In other embodiments, the dynamic power allocationsystem 200, 255 can monitor an amount of current being drawn by thevarious current loads 251 every, for example, millisecond up to aboutevery minute. The method 300 then proceeds to 315.

At 315, the TRS Controller 230 receives the current data indicating theamount of current being used by each of the various current loads 251and stores the current data into a storage portion of the TRS Controller230. The method 300 then proceeds to 330. Optionally, in someembodiments, when the dynamic power allocation system 200 is used, themethod 300 can optionally proceed to 320.

At optional 320, the TRS Controller 230 uses the current data tocalculate a load HP amount. The load HP amount is calculated based onthe current data and, for example, a power efficiency of the alternator210 to deliver current to the various current loads 251, and a powerefficiency of the drive system 225 to deliver mechanical power to thecompressor 220 and the alternator 210.

In some embodiments, the power efficiency of the alternator 210 can be afixed variable value stored in the memory portion of the TRS Controller230, where the fixed variable value is set by a user based off ofsimulation testing or the like. For example, in one embodiment using thedynamic power allocation system 200, the power efficiency of thealternator 210 can be set to a value between about ˜40% and ˜50%. Themethod 300 can then optionally proceed to 325.

At 325, the TRS Controller 230 determines a maximum available compressorHP. In some embodiments, the maximum available compressor HP isdetermined by subtracting the load HP amount from a HP of the electricdrive motor 205. Also, in some embodiments, the maximum availablecompressor HP is determined by subtracting the load HP amount from a HPof the engine 215. The method 300 then proceeds to 330.

At 330, the TRS Controller 230 controls the ETV 235 based on the maximumavailable compressor HP so as to dynamically allocate a maximumavailable horsepower to the compressor 220. In particular, the TRSController opens or closes an opening of the ETV that allows refrigerantto pass there through to the compressor based on the maximum availablecompressor HP. Accordingly, a maximum allowable horsepower can beallocated to the compressor 220 while preventing the electric drivemotor 205 and/or the engine 215 from overloading. Overloading theelectric drive motor 205 can reduce the overall life expectancy of theelectric drive motor 205 and prevent damage to portions of the electricdrive motor 205 (e.g., a motor winding insulation of the electric drivemotor 205). Overloading the engine 215 can cause the engine 215 toexceed, for example, emissions limits.

In some embodiments, when the dynamic power allocation system 255 isused, the maximum available horsepower can be the maximum availablehorsepower generated by the electric drive motor 205 because the TRUbattery charger 260 is connected directly to the external power source295 as opposed to receiving horsepower from the drive system 225. Insome embodiments, the maximum available horsepower generated by theelectric drive motor 205 can be based on physical constraints of theelectric drive motor 205 or user defined constraints of the electricdrive motor 205.

Also, in some embodiments, when the electric drive motor 205 is avariable speed drive motor that is driven by an adjustable speed drive,the dynamic power allocation system can adjust the speed of the electricdrive motor 205 based on one or more of the maximum available horsepowerand the amount of horsepower required by the compressor 220. The method300 then proceeds to 335.

At 335, the TRS Controller 230 determines whether the TRS power sourceis still operation. For example, when the power source of the TRS is theelectric drive motor 205, the electric drive motor 205 is still beingpowered by the external power source 295. If the electric drive motor205 is still being powered by the external power source 295, the method300 proceeds back to 310. Accordingly, the method 300 can continuouslyallocate a maximum available horsepower to the compressor 220 while theelectric drive motor 205 is being powered by the external power source295. If the electric drive motor 205 is no longer being powered by theexternal power source 295, the method 300 proceeds to 340 and the method300 ends.

For example, when the TRS power source is the engine 215, the engine 215is still being in an operational state for generating power. If theengine 215 is still generating power, the method 300 proceeds back to310. Accordingly, the method 300 can continuously allocate a maximumavailable horsepower to the compressor 220 while the engine 215 isgenerating power. If the engine 215 is no longer in an operation stateto generate power, the method 300 proceeds to 340 and the method 300ends.

ASPECTS

It is noted that any of aspects 1-21 can be combined.

Aspect 1. A method for dynamic power allocation in a transportrefrigeration system (TRS), the method comprising:

a TRS power source operating in an operational state;

monitoring an amount of current being drawn from one or more generatorpowered components of the TRS;

calculating, via a TRS controller of the TRS, a maximum availablehorsepower amount based on the amount of current being drawn from theone or more generator powered components; and

controlling, via the TRS controller, an amount of horsepower directed toa compressor of the TRS based on the maximum available horsepoweramount.

Aspect 2. The method according to aspect 1, further comprising the TRScontroller receiving and storing the amount of current being drawn fromthe one or more generator powered components.

Aspect 3. The method according to any of aspects 1-2, further comprisingcalculating a load horsepower amount based on an amount of current beingdrawn from the one or more generator powered components; and

calculating the maximum available horsepower amount based on the loadhorsepower amount.

Aspect 4. The method according to aspect 3, wherein calculating themaximum available horsepower amount includes:

subtracting the load horsepower amount from a horsepower of the TRSpower source.

Aspect 5. The method according to any of aspects 1-4, further comprisingcalculating the maximum available horsepower amount based on a powerefficiency of a current source of the TRS providing current to the oneor more generator powered components.

Aspect 6. The method according to any of aspects 1-5, further comprisingcalculating the maximum available horsepower amount based on a powerefficiency of a drive system of the TRS to deliver mechanical power inthe TRS.

Aspect 7. The method according to any of aspects 1-6, whereincontrolling the amount of horsepower directed to the compressorincludes:

controlling an opening of an electronic throttling valve of the TRSbased on the maximum available horsepower amount.

Aspect 8. The method according to any of aspects 1-7, wherein the TRSpower source is an electric drive motor, and

the TRS power source operating in an operational state includes anelectric power source powering the electric drive motor.

Aspect 9. The method according to any of aspects 1-7, wherein the TRSpower source is an engine, and

the TRS power source operating in an operational state includes theengine generating power.

Aspect 10. A transport refrigeration system (TRS), comprising:

a refrigeration circuit including a compressor;

a TRS power source configured to drive the compressor;

one or more generator powered components;

a current source configured to provide current to the one or moregenerator powered components; and

a TRS controller programmed to monitor in an amount of current beingdrawn from the one or more generator powered components, calculate amaximum available horsepower amount based on the amount of current beingdrawn from the one or more generator powered components, and control anamount of horsepower allocated to the compressor based on the maximumavailable horsepower amount.

Aspect 11. The TRS according to aspect 10, further comprising anelectronic throttling valve (ETV) configured to control an amount ofrefrigerant directed to the compressor,

wherein the TRS controller is programmed to control an opening of theETV in order to control the amount of horsepower allocated to thecompressor.

Aspect 12. The TRS according to any of aspects 10-11, wherein thecurrent source is at least one of an alternator and a transportrefrigeration unit (TRU) battery charger.

Aspect 13. The TRS according to any of aspects 10-12, wherein the one ormore generator powered components includes at least one of a fuelheater, a TRU battery, a solenoid valve in a host zone, a solenoid valvein a remote zone, an engine control unit, a fan and a drain tube heater.Aspect 14. The TRS according to any of aspects 10-13, wherein thecurrent source is a direct current (DC) current source.Aspect 15. The TRS according to any of aspects 10-14, wherein the TRScontroller is programmed to receive and store the amount of currentbeing drawn from the one or more generator powered components.Aspect 16. The TRS according to any of aspects 10-15, wherein the TRScontroller is programmed to calculate a load horsepower amount based onan amount of current being drawn from the one or more generator poweredcomponents, and calculate the maximum available horsepower amount basedon the load horsepower amount.Aspect 17. The TRS according to aspect 16, wherein the TRS controller isprogrammed to subtract the load horsepower amount from a horsepower ofthe TRS power source to calculate the maximum available horsepoweramount.Aspect 18. The TRS according to any of aspects 10-17, wherein the TRScontroller is programmed to calculate the maximum available horsepoweramount based on a power efficiency of the current source of the TRSproviding current to the one or more generator powered components.Aspect 19. The TRS according to any of aspects 10-18, wherein the TRScontroller is programmed to calculate the maximum available horsepoweramount based on a power efficiency of a drive system of the TRS todeliver mechanical power in the TRS.Aspect 20. The TRS according to any of aspects 10-19, wherein the TRSpower source is an electric drive motor powered by an electric powersource.Aspect 21. The TRS according to any of aspects 10-19, wherein the TRSpower source is an engine.

The terminology used in this Specification is intended to describeparticular embodiments and is not intended to be limiting. The terms“a,” “an,” and “the” include the plural forms as well, unless clearlyindicated otherwise. The terms “comprises” and/or “comprising,” whenused in this Specification, specify the presence of the stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, and/or components.

With regard to the preceding description, it is to be understood thatchanges may be made in detail, especially in matters of the constructionmaterials employed and the shape, size, and arrangement of parts withoutdeparting from the scope of the present disclosure. The word“embodiment” as used within this Specification may, but does notnecessarily, refer to the same embodiment. This Specification and theembodiments described are exemplary only. Other and further embodimentsmay be devised without departing from the basic scope thereof, with thetrue scope and spirit of the disclosure being indicated by the claimsthat follow.

What is claimed is:
 1. A method for dynamic power allocation in atransport refrigeration system (TRS), the method comprising: monitoringan amount of current being drawn by one or more loads of the TRS,wherein the one or more loads include one or more of a fuel heater, atransport refrigeration unit battery, a solenoid valve, a drain tubeheater, or an accessory load; determining a load power draw based on theamount of current being drawn by the one or more loads of the TRS;determining a maximum available power amount based on the amount ofcurrent being drawn by the one or more loads; and dynamicallycontrolling, via a controller, an amount of power directed to thecompressor of the TRS to continuously allocate the maximum availablepower amount to the compressor of the TRS.
 2. The method of claim 1,further comprising operating a TRS power source in an operational stateby providing power to an electric drive motor from an electric powersource.
 3. The method of claim 2, wherein the electric power sourceincludes one or more batteries.
 4. The method of claim 2, wherein theone or more loads are connected to a current source connected to theelectric power source.
 5. The method according to claim 4, furthercomprising calculating the maximum available power amount based on avariable corresponding to a power efficiency of the current source. 6.The method of claim 1, wherein determining the maximum available poweramount includes subtracting the load power draw from a maximum power ofa TRS power source.
 7. The method of claim 1, wherein continuouslyallocating the maximum available power to the compressor of the TRSincludes controlling an opening of an electronic throttling valve of theTRS based on the maximum available power amount.
 8. A transportrefrigeration system (TRS), comprising: a refrigeration circuitincluding a compressor; a TRS power source configured to drive thecompressor; one or more loads, wherein the one or more loads include oneor more of a fuel heater, a transport refrigeration unit battery, asolenoid valve, a drain tube heater, or an accessory load; a currentsource configured to provide current to the one or more loads; and acontroller programmed to monitor an amount of current being drawn by theone or more loads, determine a load power draw based on an amount ofcurrent being drawn by the one or more loads, determine a maximumavailable power amount based on the load power draw, and dynamicallycontrol an amount of power allocated to the compressor to continuouslyallocate the maximum available power amount to the compressor.
 9. TheTRS of claim 8, further comprising an electronic throttling valve (ETV)configured to control an amount of refrigerant directed to thecompressor, wherein the controller is programmed to control an openingof the ETV in order to control the amount of power allocated to thecompressor.
 10. The TRS of claim 8, wherein the TRS power source is anelectric drive motor connected to an electric power source, and whereinthe current source is connected to the electric power source.
 11. TheTRS of claim 9, wherein the electric power source includes one or morebatteries.
 12. The TRS of claim 8, wherein the current source is adirect current (DC) current source.
 13. The TRS of claim 8, wherein thecontroller is programmed to receive and store the amount of currentbeing drawn by the one or more loads.
 14. The TRS of claim 8, whereinthe controller is programmed to subtract the load power draw from apower of the TRS power source to calculate the maximum available poweramount.
 15. The TRS of claim 8, wherein the controller is programmed tocalculate the maximum available power amount based on a variablecorresponding to a power efficiency of the current source of the TRSproviding current to the one or more loads.